renet/src/wire/icmpv4.rs

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use core::fmt;
use byteorder::{ByteOrder, NetworkEndian};
use Error;
use super::ip::rfc1071_checksum;
enum_with_unknown! {
/// Internet protocol control message type.
pub doc enum Type(u8) {
/// Echo reply
EchoReply = 0,
/// Destination unreachable
DstUnreachable = 1,
/// Message redirect
Redirect = 5,
/// Echo request
EchoRequest = 8,
/// Router advertisement
RouterAdvert = 9,
/// Router solicitation
RouterSolicit = 10,
/// Time exceeded
TimeExceeded = 11,
/// Parameter problem
ParamProblem = 12,
/// Timestamp
Timestamp = 13,
/// Timestamp reply
TimestampReply = 14
}
}
enum_with_unknown! {
/// Internet protocol control message subtype for type "Destination Unreachable".
pub doc enum DstUnreachable(u8) {
/// Destination network unreachable
NetUnreachable = 0,
/// Destination host unreachable
HostUnreachable = 1,
/// Destination protocol unreachable
ProtoUnreachable = 2,
/// Destination port unreachable
PortUnreachable = 3,
/// Fragmentation required, and DF flag set
FragRequired = 4,
/// Source route failed
SrcRouteFailed = 5,
/// Destination network unknown
DstNetUnknown = 6,
/// Destination host unknown
DstHostUnknown = 7,
/// Source host isolated
SrcHostIsolated = 8,
/// Network administratively prohibited
NetProhibited = 9,
/// Host administratively prohibited
HostProhibited = 10,
/// Network unreachable for ToS
NetUnreachToS = 11,
/// Host unreachable for ToS
HostUnreachToS = 12,
/// Communication administratively prohibited
CommProhibited = 13,
/// Host precedence violation
HostPrecedViol = 14,
/// Precedence cutoff in effect
PrecedCutoff = 15
}
}
enum_with_unknown! {
/// Internet protocol control message subtype for type "Redirect Message".
pub doc enum Redirect(u8) {
/// Redirect Datagram for the Network
Net = 0,
/// Redirect Datagram for the Host
Host = 1,
/// Redirect Datagram for the ToS & network
NetToS = 2,
/// Redirect Datagram for the ToS & host
HostToS = 3
}
}
enum_with_unknown! {
/// Internet protocol control message subtype for type "Time Exceeded".
pub doc enum TimeExceeded(u8) {
/// TTL expired in transit
TtlExpired = 0,
/// Fragment reassembly time exceeded
FragExpired = 1
}
}
enum_with_unknown! {
/// Internet protocol control message subtype for type "Parameter Problem".
pub doc enum ParamProblem(u8) {
/// Pointer indicates the error
AtPointer = 0,
/// Missing a required option
MissingOption = 1,
/// Bad length
BadLength = 2
}
}
/// A read/write wrapper around an Internet Control Message Protocol version 4 packet buffer.
#[derive(Debug)]
pub struct Packet<T: AsRef<[u8]>> {
buffer: T
}
mod field {
#![allow(non_snake_case)]
use wire::field::*;
pub const TYPE: usize = 0;
pub const CODE: usize = 1;
pub const CHECKSUM: Field = 2..4;
pub const ECHO_IDENT: Field = 4..6;
pub const ECHO_SEQNO: Field = 6..8;
}
impl<T: AsRef<[u8]>> Packet<T> {
/// Wrap a buffer with an ICMPv4 packet. Returns an error if the buffer
/// is too small to contain one.
pub fn new(buffer: T) -> Result<Packet<T>, Error> {
let len = buffer.as_ref().len();
if len < field::CHECKSUM.end {
Err(Error::Truncated)
} else {
let packet = Packet { buffer: buffer };
if len < packet.header_len() {
Err(Error::Truncated)
} else {
Ok(packet)
}
}
}
/// Consumes the packet, returning the underlying buffer.
pub fn into_inner(self) -> T {
self.buffer
}
/// Return the message type field.
#[inline(always)]
pub fn msg_type(&self) -> Type {
let data = self.buffer.as_ref();
Type::from(data[field::TYPE])
}
/// Return the message code field.
#[inline(always)]
pub fn msg_code(&self) -> u8 {
let data = self.buffer.as_ref();
data[field::CODE]
}
/// Return the checksum field.
#[inline(always)]
pub fn checksum(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::CHECKSUM])
}
/// Return the identifier field (for echo request and reply packets).
///
/// # Panics
/// This function may panic if this packet is not an echo request or reply packet.
#[inline(always)]
pub fn echo_ident(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::ECHO_IDENT])
}
/// Return the sequence number field (for echo request and reply packets).
///
/// # Panics
/// This function may panic if this packet is not an echo request or reply packet.
#[inline(always)]
pub fn echo_seq_no(&self) -> u16 {
let data = self.buffer.as_ref();
NetworkEndian::read_u16(&data[field::ECHO_SEQNO])
}
/// Return the header length.
/// The result depends on the value of the message type field.
pub fn header_len(&self) -> usize {
match self.msg_type() {
Type::EchoRequest => field::ECHO_SEQNO.end,
Type::EchoReply => field::ECHO_SEQNO.end,
_ => field::CHECKSUM.end // make a conservative assumption
}
}
/// Return a pointer to the type-specific data.
#[inline(always)]
pub fn data(&self) -> &[u8] {
let data = self.buffer.as_ref();
&data[self.header_len()..]
}
/// Validate the header checksum.
pub fn verify_checksum(&self) -> bool {
let checksum = {
let data = self.buffer.as_ref();
rfc1071_checksum(field::CHECKSUM.start, &data[..self.header_len()])
};
self.checksum() == checksum
}
}
impl<T: AsRef<[u8]> + AsMut<[u8]>> Packet<T> {
/// Set the message type field.
#[inline(always)]
pub fn set_msg_type(&mut self, value: Type) {
let mut data = self.buffer.as_mut();
data[field::TYPE] = value.into()
}
/// Set the message code field.
#[inline(always)]
pub fn set_msg_code(&mut self, value: u8) {
let mut data = self.buffer.as_mut();
data[field::CODE] = value
}
/// Set the checksum field.
#[inline(always)]
pub fn set_checksum(&mut self, value: u16) {
let mut data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::CHECKSUM], value)
}
/// Set the identifier field (for echo request and reply packets).
///
/// # Panics
/// This function may panic if this packet is not an echo request or reply packet.
#[inline(always)]
pub fn set_echo_ident(&mut self, value: u16) {
let mut data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::ECHO_IDENT], value)
}
/// Set the sequence number field (for echo request and reply packets).
///
/// # Panics
/// This function may panic if this packet is not an echo request or reply packet.
#[inline(always)]
pub fn set_echo_seq_no(&mut self, value: u16) {
let mut data = self.buffer.as_mut();
NetworkEndian::write_u16(&mut data[field::ECHO_SEQNO], value)
}
/// Return a mutable pointer to the type-specific data.
#[inline(always)]
pub fn data_mut(&mut self) -> &mut [u8] {
let range = self.header_len()..;
let mut data = self.buffer.as_mut();
&mut data[range]
}
/// Compute and fill in the header checksum.
pub fn fill_checksum(&mut self) {
let checksum = {
let data = self.buffer.as_ref();
rfc1071_checksum(field::CHECKSUM.start, &data[..self.header_len()])
};
self.set_checksum(checksum)
}
}